A great variety of bleaching and cleaning compositions have been described in the art. Bleaching/cleaning compositions comprising a source of active oxygen and formulated at low pH are particularly interesting for the cleaning of hard-surfaces, especially for the hygienic cleaning of sanitary fittings such as toilet bowls and the like.
European co-pending application 94870184.2 discloses acidic thickened aqueous compositions comprising persulfate salts and as the thickening system a quaternary ammonium compound together with a short chain amine oxide (C6 to C10).
It is desirable to formulate acidic compositions comprising a source of active oxygen such as persulfate salts with an adequate viscosity, so that said compositions have a consumer acceptable residence time on the surface to be cleaned. In other words, it is desired from a consumer point of view to provide compositions having greater residence time on non-horizontal surfaces such as inclined wall of a toilet bowl when applied thereto, allowing thereby that said compositions perform their cleaning action for longer periods of time. It has now been found that the consumer perception of the viscosity of a given thickened composition applied onto a non-horizontal surface is driven not only by the real viscosity of said composition per se but even by the level of dye present in said composition. Indeed, it has been observed that the higher the dye level, the thicker the composition is perceived by the consumer when applied on a non-horizontal surface like toilet bowls.
It is further desirable that such compositions be easily rinsed away from said surfaces, especially because viscous products have a good cling onto said surfaces. We have now found that the consumer perception of the rinsing of a given thickened composition applied onto a non-horizontal surface like toilet bowls, is driven not only by the real amount of said composition that remains onto said surface after having being rinsed away for example by flushing, but also by the level of dye present in said composition. It has been observed that the higher the dye level, the more product is perceived by the consumer to remain on said surface after flushing, which is detrimental from a consumer point of view.
It is thus an object of the present invention to formulate colored acidic thickened aqueous compositions comprising a source of active oxygen and a dye, said compositions being perceived concomitantly as being more viscous and easy to rinse away from a consumer standpoint.
Also, when formulating colored acidic aqueous compositions, which comprise a source of active oxygen such as monopersulfate salts, stability problems appear, i.e., in general peroxy-bleaches raise compatibility issues in relation with the kind of dyes used and the levels of dyes because dyes themselves and/or the metals present in the dyes may catalyse the peroxide decomposition.
It is thus also an object of the present invention to provide a colored acidic thickened aqueous composition comprising a source of active oxygen, in particularly a persulfate salt, which is chemically stable.
It has now been found that the above mentioned objects could be met by formulating acidic thickened aqueous compositions comprising a source of active oxygen with a dye which is chemically and physically stable in said medium, i.e., an .alpha. or .beta. metal phthalocyanine dye, or mixtures thereof at optimised levels. Indeed, it has been found that by carefully defining the level of said .alpha. or .beta. metal phthalocyanine dye, or mixtures thereof, compositions are perceived thicker by the consumer while being also easily rinsed away from a non-horizontal surface after having been applied thereto. In other words, the present invention allows to provide colored acidic thickened aqueous compositions which are perceived by the consumer as being more viscous, without increasing the total level of thickening ingredients present in said compositions such as surfactants. Also the present invention allows to optimise the rinsing perception by the consumer of colored acidic thickened aqueous compositions without decreasing the real viscosity of said compositions and/or modifying the hydrophilicity/lipophilicity balance (HLB) of said compositions.
An advantage of the compositions of the present invention is that said compositions are chemically stable for long storage periods. Indeed, by carefully defining the level of .alpha. or .beta. metal phthalocyanine dyes, or mixtures thereof, chemically stable colored acidic aqueous compositions are provided.
A further advantage of the present invention is that said colored acidic thickened aqueous compositions are efficient on various surfaces to clean various soils and stains. Additionally, said compositions when used to treat hard surfaces, especially toilet bowls, exhibit outstanding soil discoloration, soil solubilization, removal and emulsification properties together with a germicidal action, this when used both neat or diluted.
Also, the preferred thickened compositions of the present invention which comprise a thickening surfactant system comprising quaternary ammonium compound and short chain amine oxide (C6-C10), exhibit improved thickening properties at low total thickening surfactant level.
The following patent applications are representative of the prior art.
EP-A-265 979 discloses acidic thickened aqueous cleaning compositions comprising a disinfecting and/or oxidising agent, an organic anionic sulphonate and a surfactant selected from the group of (1) quaternary ammonium compounds wherein at least one of the hydrocarbon groups linked to the nitrogen is a linear or branched alkyl group containing at least 12 carbon atoms and of (2) tertiary amine oxides wherein at least one of the hydrocarbon groups linked to the nitrogen is a linear or branched alkyl group containing at least 16 carbon atoms. Nowhere in EP-A-265 979 a source of active oxygen is disclosed. The composition in example 1 comprises a dye at a level of 0.001% by weight.
EP-A-188 025 discloses aqueous stable thickened low-pH bleaching compositions comprising an inorganic peroxy compound, a strong acid and a thickening surfactant. Dyes are mentioned in general. The examples comprise Latex red 41R, or Latex blue 842103 which are not .alpha. or .beta. metal phthalocyanine dyes.
EP-A-601 792 discloses thickened aqueous toilet cleaning compositions comprising an acidic limescale removing agent, hydrogen peroxide, one or more thickeners and up to 1.5% by weight of a colorant. The composition exemplified comprises Unisperse green.RTM. which is a chlorinated copper phthalocyanine dye at a level of 0.0045% by weight. No reference is made to the finding of the present invention, the existence of optimised levels of .alpha. or .beta. metal phthalocyanine dyes which enable to have excellent perceived viscosity and excellent perceived ease of rinsing without compromising peroxy-bleach stability.